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Jet Propulsion Lab. - Jim Janesick.

Jim Janesick is involved in a variety of new techniques for improving the overall response of CCD detectors. This work was concerned with the following:-

For the HST - A proposed WIFPIC III camera. This utilised a thin gate, front-side illuminated device, whereby one of the clock phase electrodes is made thinner than normal to enhance the peak response. Lumogen is then applied to obtain the required UV response.

For back-thinned CCDs he is proposing a Molecular-Beam-Epitaxy process to achieve a Boron surface layer. This charges the surface enabling UV photo-electron charge collection. However this process is both expensive and not very practicable.

Janesick also described some devices which can be used for fast-read applications. The chip used by Cassini has every alternate line in the imaging area covered by an Aluminium strip. This enables 2 images to be stored on the chip at one time (in much the same way as a frame transfer array), separated in time by 500ns, the time taken to move the imaging pixels into the store area was quoted as being 200ns.

A second device consisted of a array with a floating diffusion amplifier on each column so there is no serial register. The amplifiers can be operated in skipper mode if required and have a read-noise of . It is possible to read these devices at .

A third device consisted of an array of pixels with 2, high-speed amplifiers. The read-noise was stated to be not very low but the device could be read at 30-40 million pixels-per-second.
Fri Sep 9 14:55:39 BST 1994